How to Figure Out the Size of HVAC You Need

When people look for a new HVAC system for their home, one of the vital things that require careful deliberation is figuring out the correct unit size to heat and cool the interiors efficiently. An HVAC system is an expensive piece of equipment that plays a vital role in determining a home's comfort. 

Purchasing an incorrectly sized unit would mean a waste of money, energy, and compromised comfort and functionality. Correctly sizing the system is critical for several reasons. An undersized system fails to provide the desired heating and cooling through the house. Installing an oversized unit means higher initial cost, waste of money, energy, and shorter system lifespan.

Several buyers feel overwhelmed and confused about figuring out the perfect HVAC unit size matching their home needs. We discuss here the ways to determine the correct size of a heating and cooling system for a homeowner:

Measure the square footage

The first step to determine the HVAC system size is calculating the home's square footage or the area that requires heating and cooling. If the information is not available, homeowners can easily make the calculations. Use a measuring tape to measure the length and width of a room and multiply them together to get the square footage of that particular room. Follow a similar process for all the other areas in the house, and in the end, add up all the numbers to determine the square footage of the entire home.

Obtain the base BTU value

British Thermal Unit or BTU is a measuring unit for calculating the energy used for heating and cooling a home. According to experts, around 25 BTUs are required to heat and cool a home's single square footage. Multiply the total square footage of the home derived earlier by 25 to get the base BTU value. For example, a 1000 square feet home will require around 25000 BTUs. 

Divide the obtained BTU number by 12000 to figure out the estimated tonnage for the air conditioner. For a 1000 square feet home, a 2 tons unit would suffice. For the furnace, divide the calculated base BTU by the figure obtained by converting the efficiency percentage into a decimal number. For example, a 90% efficient system would require a BTU output of about 28000 BTU.

Pick the right unit

The best way to arrive at a decision is to consult an HVAC contractor. The basic calculation mentioned above fails to take into account several essential factors. Professionals use Manual J calculation which takes into account several critical aspects. These factors include ductwork system, square footage, windows and doors, and their style and condition. The calculation also accounts for insulation, climate zone, ceiling height, lighting and ventilation systems, occupancy, heat-generating appliances, environment, and attic, garage, and basement to obtain more accurate measurements. 

Get an energy audit

An HVAC technician can perform an energy audit to get a customized BTU figure to determine the exact HVAC system size that provides optimum efficiency and comfort needed for a home.

HVAC experts suggest purchasing a higher unit size if the exact unit size is not available. However, ensure not to choose a too big unit. When purchasing the system, avoid going 15% over the BTUs recommended for air conditioning, 40% for furnace, and 25% for the heat pump.

Evenflow Home Services specializes in heat pump repair, heat pump replacement, HVAC replacement, HVAC blower motor, condenser coil, evaporator coil, and emergency heat pump repair. Call us at (210) 941-3503